import { Vector3 } from './Vector3'

export class GcjBD {
    // readonly type: string
    lon: number
    lat: number
    height: number
    PI: number
    x_pi: number
    constructor(position: Vector3) {
        this.lon = position.x
        this.lat = position.y
        this.height = position.z  
        this.PI = 3.14159265358979324
        this.x_pi = 3.14159265358979324 * 3000.0 / 180.0
    }
    // WGS-84 to GCJ-02
    gcj_encrypt(): {lon: number, lat: number, height: number} {
            if (this.outOfChina(this.lon, this.lat)) { return {'lon': this.lon, 'lat': this.lat, 'height': this.height} }
            const change = this.delta(this.lon, this.lat)
            return {'lon': this.lon + change.lon, 'lat': this.lat + change.lat, 'height': this.height}
        }
    // GCJ-02 to WGS-84
    gcj_decrypt() {
            if (this.outOfChina(this.lon, this.lat)) { return {'lon': this.lon, 'lat': this.lat, 'height': this.height} }
            const change = this.delta(this.lon, this.lat)
            return {'lon': this.lon - change.lon, 'lat': this.lat - change.lat, 'height': this.height}
        }
    // BD-09 to GCJ-02
    bd_decrypt() {
            if (this.outOfChina(this.lon, this.lat)) { return {'lon': this.lon, 'lat': this.lat, 'height': this.height} }
            const x = this.lon - 0.0065; var y = this.lat - 0.006
            const z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * this.x_pi)
            const theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * this.x_pi)
            const gcjLon = z * Math.cos(theta)
            const gcjLat = z * Math.sin(theta)
            this.lon = gcjLon
            this.lat = gcjLat
            const lonlat = this.gcj_decrypt()
            return {'lon': lonlat.lon, 'lat': lonlat.lat, 'height': this.height}
          }
    outOfChina(lon: number, lat: number): boolean {
            if (lon < 72.004 || lon > 137.8347) { return true }
            if (lat < 0.8293 || lat > 55.8271) { return true }
            return false
        }  
    delta(lon : number, lat : number) {
            const a = 6378245.0 //  a: 卫星椭球坐标投影到平面地图坐标系的投影因子。
            const ee = 0.00669342162296594323 //  ee: 椭球的偏心率。
            let dLon = this.transformLon(lon - 105.0, lat - 35.0)
            let dLat = this.transformLat(lon - 105.0, lat - 35.0)
            const radLat = lat / 180.0 * this.PI
            let magic = Math.sin(radLat)
            magic = 1 - ee * magic * magic
            const sqrtMagic = Math.sqrt(magic)
            dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * this.PI)
            dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * this.PI)
            return {'lon': dLon, 'lat': dLat}
          }
          transformLon(x : number, y : number) {
            let ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x))
            ret += (20.0 * Math.sin(6.0 * x * this.PI) + 20.0 * Math.sin(2.0 * x * this.PI)) * 2.0 / 3.0
            ret += (20.0 * Math.sin(x * this.PI) + 40.0 * Math.sin(x / 3.0 * this.PI)) * 2.0 / 3.0
            ret += (150.0 * Math.sin(x / 12.0 * this.PI) + 300.0 * Math.sin(x / 30.0 * this.PI)) * 2.0 / 3.0
            return ret
          }
          transformLat(x : number, y : number) {
            let ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x))
            ret += (20.0 * Math.sin(6.0 * x * this.PI) + 20.0 * Math.sin(2.0 * x * this.PI)) * 2.0 / 3.0
            ret += (20.0 * Math.sin(y * this.PI) + 40.0 * Math.sin(y / 3.0 * this.PI)) * 2.0 / 3.0
            ret += (160.0 * Math.sin(y / 12.0 * this.PI) + 320 * Math.sin(y * this.PI / 30.0)) * 2.0 / 3.0
            return ret
          }
}